The concept of membranes incorporating ionophores, the conductance of which are gated and the use of such membrane in biosensors is disclosed in International patent application Nos WO89/01159, WO90/08783, PCT/AU89/00352, PCT/AU92/00132 and PCT/AU93/00509. The disclosure of each of these documents is incorporated herein by reference.
The present invention stems from an observation made by the present inventor during the work conducted and disclosed in International application No WO90/08783. In this earlier application it was shown that the conduction of biotinylated gramicidin ion channels in a lipid membrane is greatly reduced by the binding of streptavidin by the biotins attached to the gramicidin, and that the changing conduction in this system is directly related to the quantity of streptavidin bound to the membrane ion channels. From this observation the present inventor has developed a general mechanism for analyte detection using a membrane incorporating ionophores.